Open time additive for cementitious tile adhesives mortar

Abstract

The invention includes dry mix mortar formulations including an Innovative Additive, which includes clay, cellulose, and starch, and methods of making the formulations. The clay includes Smectite clay and / or Attapulgite clay, and the Smectite clay includes one or more of hectorite,bentonite, and Sepiolite. The dry mix mortar formulations when combined with water to form wet tile mortars provide improved properties including ease of application, durability, sag control, water retention, viscosity buildup, and extended open time, as well as exhibiting a tensile adhesion strength that meets or exceeds 72.5 psi after a 30-minute open time period.

Description

OPEN TIME ADDITIVE FOR CEMENTITIOUSTILE ADHESIVES MORTARCross-Reference to Related Application

[0001] This application claims priority to and the benefit of U. S. Provisional Application No.63 / 718,866, filed on November 11, 2024, the disclosure of which is incorporated herein by reference in its entirety.Field of the Invention

[0002] The invention relates to dry mix mortar formulations that include an innovative additive containing clay, cellulose and starch, as well as methods of making the formulations. The dry mix mortar formulations provide improved properties including ease of application, durability, sag control, water retention, viscosity buildup, and extended or prolonged open time.Background

[0003] Dry mix mortar (“dry mortar”) is a powder mixture of sand and a binder (e.g., cement) along with other additives and fillers. The addition of water to the dry mortar generates a paste (“wet mortar”) which will chemically react and cure over time. Wet mortar used as a paste hardens and fuses masonry components such as tile, concrete, and other construction materials. In addition to cement tiles, ceramic tiles have attained a distinctive focus due to their decorative feature for both indoor and outdoor conditions, and for their ease of implementation. When it comes to the adhesion of these tiles onto a substrate, e.g., wall or floor, tile adhesives are used for their installation and fixation. Performance criteria for tile adhesives include tensile adhesion strength, open time, and slip resistance. Also, an extended open time is a key feature of a cement-based tile adhesive for tiling as well as for other dry mortar applications. Extended open times for mortars are highly desirable when installing tiles in drier climate zones, in exterior applications where windy conditions often prevail, and when installing very large-sized tiles (large format tiles) that require more time for adjusting grout lines. In general, the more porous the substrate and the more water absorptive is the tile, the less time an installer has available to lay the tiles. While a typical mortar may result in loss of bonding adhesion strength, a tile adhesive with extended open-time properties will give the installer the necessary time to apply the tiles and achieve the optimal tile adhesion strength once the mortar has cured.

[0004] Traditional methods that use sand-cement mortar result in some drawbacks such as poor water retention, hardness and brittleness of the surface, higher drying time, and increased thicknessof paste which reduces its spreadability. Tt is generally known in the art to use chemical additives to modify mortars and concretes to obtain standard required properties or special enhanced properties. Mortar formulations include various chemical additives wherein even a small amount of each additive can have a significant effect on the properties of wet and cured mortars. The effect of the additives on the properties of the mortars is varied and depends on several factors. The selection of the type of additives and their amounts consist of a compromise between obtaining the appropriate consistency and rheological properties, e.g., ensuring adequate fluidity, plasticity, and non- segregation, good workability, and high-water retention which ensures the appropriate conditions for hydration, as well as the mortar setting and hardening processes, and reduction of shrinkage deformation.

[0005] Generally, mortar formulations include one or more of the following ingredients.1. Dry Cement

[0006] Cement is a pivotal material in global construction, acting as a binding agent when mixed with sand, gravel, and water to form concrete. This mixture is essential for providing strength and durability to various structures. The market offers a diverse range of cements, each with unique properties tailored to specific construction needs and applications. Examples include Ordinary Portland Cement (OPC), Portland Pozzolana Cement (PPC), rapid hardening cement, slag cement, high alumina cement, quick setting cement, and recently developed Green Cement.

[0007] Various standards classify and define cements, such as ASTM C 150 / C 150M-22, ASTM C595. ASTM C1157, and EN 197-1. For instance, the research Examples included herein, used Type I / II cement from the Ordinary Portland Cement category as defined in ASTM C150.2. Dry Sand

[0008] Sand is one of the oldest building materials used throughout the centuries in various construction projects. Sand provides strength, bulk, and stability to concrete, masonry, asphalt and cement. Not all sand is the same. Some sand has rocks and impurities like clay, salt, topsoil or vegetation. These impurities can detract from the final performance properties of the cured cement which makes them less desirable for use in construction formulations. Impure sand adversely affects the formation of proper bonds between the cement and sand. Poor bonds make the structure less sturdy and weak; hence, the optimal type of sand should be used. Sand and coarse aggregate can be mixed with lime or cement to create concrete, as well as high-quality mortar for plasters and for jointing bricks or stone. There are three main sources of sand: river sand, crushed sand,and pit sand. Different types of sand can be composed of different chemical compositions such as silicates, carbonates, or calcium sulphate.

[0009] The various types of sand include, but are not limited to, utility sand, masonry sand, concrete sand, fill sand, industrial sand, crushed stone sand, and fined crushed limestone gravel.

[0010] River sand is ideal for usage in concrete, masonry work, plastering, reinforced cement concrete (RCC). and other block work due to its high silica content and high moisture content, which means it does not require a high amount of water when used in construction applications. Manufactured sand (or M-sand) is a more sustainable alternative to river sand. Unlike natural sand, M-sand contains no organic impurities that could damage structures over time. Additionally, M-sand is less expensive than natural sand due to the efficient production process that includes several crushing cycles by blasting and crushing quarry stones and rocks, then sieving and washing to ensure the M-sand is free from impurities that would weaken concrete or screed.

[0011] Silica sands are available in various U. S. mesh (sieve) sizes ranging from 4 to 200 corresponding to different millimeter sizes, each suitable for specific applications. A lower U. S. mesh size of silica sand corresponds to a coarser size distribution, and is commonly used for abrasive blasting, filtration systems, and concrete mixes; while higher U. S. mesh size silica sand refers to a finer size distribution, and is preferred for glass manufacturing, ceramics, and metal casting.3. Dry Polymer Additive

[0012] It is generally known to incorporate polymer(s) into Portland cement as property enhancer(s). For example, polymer(s) has been used to improve water retention, permeability, adhesive strength, workability and deformability of mortars and concretes, as well as other properties. The polymer(s) creates a coating on the cement and aggregate paste, reducing the permeability of the concrete and, consequently, its capacity to retain water; thereby providing the required flexural strength, tensile adhesion strength, and other like properties. Ethylene-vinyl acetate (VAE) copolymer powder(s) and dispersions have been shown to improve performance of the cement mortar and are widely used.4. Cellulose Additive (e.g., Methyl Hydroxyethyl Cellulose)

[0013] Cellulose is a natural polysaccharide. Pure cellulose is a white, water-insoluble substance, which requires being subjected to an industrial process to be used as a chemical admixture. Among the various cellulose derivatives, the following cellulose ethers (e.g., nonionic cellulose ethers) arecommonly used in cement-treated aggregate (CTA) applications: methyl hydroxyethyl cellulose (MHEC), methyl hydroxypropyl cellulose (MHPC), hydroxypropyl cellulose (HPC), methyl cellulose (MC), ethyl hydroxyethyl cellulose (EHEC), methyl ethyl hydroxyethyl cellulose (MEHEC), and hydroxyethyl cellulose (HEC). Addition of the cellulose derivative(s) to any construction mortar, including CTA, often causes retardation of the cement hydration and thereby results in cure retardation, increases plasticity, affects the viscosity, improves the workability, and ensures higher water retention in the mortar. The presence of the cellulose derivative, e.g., cellulose ether, influences the properties of both the wet and hardened adhesive. The water stored by the cellulose ethers provide the appropriate conditions for setting and hardening of the cementitious binders. Cellulose ethers, due to the specific function of the water storage, have a positive effect on the strength parameters of the mortars, including their adhesion to the substrate.5. Starch Additive

[0014] Starch is a natural polymer derived from the polysaccharide group. It is most often obtained from potatoes or corn. Due to its physiochemical properties, the use of unmodified starch is quite limited in construction applications. To improve this limitation, the starches are physically and chemically modified to give them desired performance characteristic parameters, such as solubility, and improved texture and consistency. It is generally known to add starch ethers to dry mix mortars or concretes to enhance workability and reduce segregation of the components of the mortars or concretes. In addition, starch ethers cause the prolongation of the open time, which is, however, accompanied by a setting delay (retardation). As is known, with a shorter setting delay there is also a shortened open time. The starch ethers are predominantly hydroxypropyl starches, hydroxypropyl carboxymethyl starches, also partially cross linked, and carboxymethyl starches.6. Water

[0015] Water is a critical part of the mortar formula and is required to transform the dry powder mortar into a wet mortar. In addition to providing liquid fluidity to the powder mixture, it facilitates structural transformation of mortar components such as the starch and cellulose into hydrated structural shapes of the particles and the molecules which are beneficial to the application characteristics of the mortar mixture. The water also hydrates and chemically reacts with the cement powder leading to the cured, hard mortar which is the desired end product. The amount of water used in the mortar formula can significantly impact the workability, wet application characteristics, and final performance properties of the cured mortar. The amount of water usedin a mortar is commonly referred to as “water demand” and is the amount of water in grams of added water per 100 grams of mortar powder. Typical water demand of commercial mortars can be in the range of 18 grams to 24 grams of water per 100 grams of mortar powder. Depending on the particular mortar composition, the water demand can vary from a few grams of water up to hundreds of grams of water per 100 grams of mortar powder. Water demand may be determined by those experienced in the art by simply adding water to the mortar powder until an acceptable mixing consistency that is desirable for the application is achieved, by hand mixing it and visually observing how it mixes and adheres to a raised spatula. Another approach to determine water demand is to use a flow table as described in ASTM C1437, and to add water to the mortar powder until a certain flow which is acceptable is achieved. The flow table test starts by placing a measured aliquot of mortar in the center of the table platform. A handle is turned the number of times and at a rate according to the test method. The turning of the handle causes the platform to repeatedly raise a small amount and then it immediately slams back down to a hard stop. As a result of this repeated jarring, the aliquot spreads to a circle of a certain diameter. At the end of this test, the diameter of the mortar circle is measured. For a particular mortar formula and application, the spread mortar diameter can be correlated to be an indicator of certain application characteristics (viscosity, levelling, wet adhesion) and of the final cured performance.

[0016] In general, the drawbacks of dry mix mortars are known in the art, including low tensile strength, low chemical resistance, and significant drying shrinkage. It is desirable to provide dry mortar formulations which, when used as adhesives or coating materials, exhibit good tensile bond strength that results in extended or prolonged open time.

[0017] Thus, an object of the invention is to provide dry mix mortar formulations, such as cementitious tile adhesives, that include an innovative additive which includes one or more of hectorite, bentonite, Sepiolite and Attapulgite to significantly reduce the setting retardation and also extend or prolong open time, and coincident therewith ensures other important properties, such as, one or more of the following being improved and / or maintained: (i) ease of application, (ii) durability, (iii) sag control, (iii) water retention, and (iv) viscosity buildup.SUMMARY OF THE INVENTION

[0018] In one aspect, the invention provides a dry mix mortar formulation including sand; cement; and Innovative Additive that includes a clay including one or more of bentonite, hectorite,Sepiolite and Attapulgite; a cellulose; and a starch, wherein, the dry mix mortar formulation when combined with water to form a wet mortar demonstrates an extended open time.

[0019] In certain embodiments, the clay is present in a range having a lower endpoint of 5 weight percent and an upper endpoint of 90 weight percent or a lower endpoint of 40 weight percent and an upper endpoint of 80 weight percent, based on the total weight of the Innovative Additive.

[0020] In certain embodiments, the cellulose is present in a range having a lower endpoint of 5 weight percent and an upper endpoint of 90 weight percent or a lower endpoint of 10 weight percent and an upper endpoint of 30 weight percent, based on the total weight of the Innovative Additive.

[0021] In certain embodiments, the starch is present in a range having a lower endpoint of 2 weight percent and an upper endpoint of 40 weight percent or a lower endpoint of 5 weight percent and an upper endpoint of 20 weight percent, based on the total weight of the Innovative Additive.

[0022] In certain embodiments, the cellulose is selected from methyl hydroxyethyl cellulose, methyl hydroxypropyl cellulose, hydroxyethyl cellulose, and combinations and mixtures thereof.

[0023] In certain embodiments, the starch is selected from hydroxypropyl starch, hydroxypropyl carboxymethyl starch, carboxymethyl starch, and combinations and mixtures thereof.

[0024] In certain embodiments, the Innovative Additive is present in a range having a lower endpoint of 0.1 weight percent and an upper endpoint of 7.0 weight percent or a lower endpoint of 0.5 weight percent and an upper endpoint of 4.0 weight percent, based on the total weight of the dry mix mortar formulation.

[0025] In certain embodiments, the Innovative Additive includes 85% by weight of the clay; 10% by weight of the cellulose; and 5% by weight of the starch, based on the total weight of the Innovative Additive.

[0026] In certain embodiments, the starch is a starch ether.

[0027] In certain embodiments, the sand comprises silica.

[0028] In certain embodiments, the silica has a mesh (sieve) size from 4 to 200.

[0029] In certain embodiments, the sand comprises from 30 to 80 weight percent or from 50 to 70 weight percent, based on the total weight of the dry mix mortar formulation.

[0030] In certain embodiments, the cement comprises from 20 to 50 weight percent or from 22 to 40 weight percent, based on the total weight of the dry mix mortar formulation.

[0031] In certain embodiments, the dry mix mortar formulation further includes one or more of a polymer, cure accelerator, colored pigment, filler, and combinations or blends thereof. The polymer may be selected from the group consisting of styrene-acrylic, vinyl acetate ethylene copolymer, polyvinyl acetate, acrylic, styrene butadiene rubber, and combinations or blends thereof. In certain embodiments, the polymer is present in a range having a lower endpoint of 1, 1.5 or 10 weight percent and the upper end point is 20. 15. or 10, based on the total weight of the dry mix mortar formulation.

[0032] In certain embodiments, the dry mix mortar formulation includes 0.5 weight percent of the Innovative Additive; 33 weight percent of the cement; 65 weight percent of the silica; and 1.5 weight percent of the polymer, based on the total weight of the dry mix mortar formulation.

[0033] In another aspect, the invention provides a wet tile mortar formulation including the foregoing dry mix mortar formulation and water. In certain embodiments, the wet tile mortar formulation is based on a percentage of water the water demand is 22.3%. In certain embodiments, the tensile adhesion strength meets or exceeds 72.5 psi (0.5 N / mm2) after a 30-minute open time period. In certain embodiments, the tensile adhesion strength meets or exceeds 72.5 psi (0.5 N / mm2) after a 45 -minute open time period.

[0034] A method for preparing a dry mix mortar formulation. The method includes preparing an Innovative Additive that includes combining a clay comprising one or more of bentonite, hectorite, Sepiolite and Attapulgite; a cellulose; and a starch; and mixing the Innovative Additive with cement and sand.

[0035] In certain embodiments, the method further includes combining the dry mix mortar formulation with water forming a wet mortar that demonstrates an extended open time. In certain embodiments, the cellulose is selected from methyl hydroxyethyl cellulose, methyl hydroxypropyl cellulose, hydroxypropyl cellulose, methyl cellulose, ethyl hydroxyethyl cellulose, methyl ethyl hydroxyethyl cellulose, and hydroxyethyl cellulose, and combinations and mixtures thereof. In certain embodiments, the starch is selected from hydroxypropyl starch, hydroxypropyl carboxymethyl starch, carboxymethyl starch, and combinations and mixtures thereof.

[0036] In another aspect, the invention includes a method for preparing a wet mortar formulation including preparing the dry mix mortar formulation; and adding water to the dry mix mortar formulation. In certain embodiments, this method can include the steps of preparing the dry tile mortar formulation and adding water to the dry tile mortar formulation.BRIEF DESCRIPTION OF THE DRAWINGS

[0037] FIG. 1 is an image that illustrates ten square blocks of tile that are each set in a troweled layer of adhesive composition that is applied to a concrete slab for 30 minutes and ten square blocks of tile that are each set in a troweled layer of adhesive composition that is applied to a concrete slab for 45 minutes, in accordance with certain embodiments of the invention.

[0038] FIG. 2 is a bar graph that illustrates 28-day tile mortar open time tile adhesion tensile pull test results at 30 minutes and 45 minutes, in accordance with certain embodiments of the invention.

[0039] FIG. 3 is a bar graph that illustrates water demand, i.e., grams of water per 100 grams of mortar, in accordance with certain embodiments of the invention.

[0040] FIG. 4 is a bar graph that illustrates 28-day tile mortar open time tile adhesion tensile pull test results at 30 minutes and 45 minutes, in accordance with certain embodiments of the invention.

[0041] FIG. 5 is an image that illustrates a tile slip test that includes a square block of tile set in a troweled layer of adhesive composition that is applied to a vertically positioned concrete slab, in accordance with certain embodiments of the invention.DETAILED DESCRIPTION

[0042] Unless otherwise noted, technical terms are used according to conventional usage. Unless otherwise explained, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. The singular terms “a,” “an,” and “the” include plural referents unless context clearly indicates otherwise. Similarly, the word “or” is intended to include “and” unless the context clearly indicates otherwise. The term “comprises” means “includes.” The abbreviation, “e.g.” is derived from the Latin exempli gratia and is used herein to indicate a non-limiting example. Thus, the abbreviation “e.g.” is synonymous with the term “for example.” Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of this disclosure, suitable methods and materials are described below. In addition, the materials, methods, and examples are illustrative only and not intended to be limiting.

[0043] The word “tile(s)” include(s) cement floor tile(s), glazed ceramic floor tile(s), vitrified tile(s), porcelain tile(s), glazed ceramic wall tile(s), natural stone tile(s), cultured stone tile(s), and marble tile(s).

[0044] The invention relates to dry mix mortar formulations, such as but not limited to tile adhesives, and methods of making the formulations. The dry mix mortar formulations according to the invention provide improvements as compared to traditional formulations, such as, one or more of (i) ease of application, (ii) durability, (iii) sag control, (iv) water retention, (v) viscosity buildup, (vii) tile slide resistance, and (vii) extended or prolonged open time.

[0045] The innovative additive formulations according to the invention are used in a wide variety of applications including but not limited to adhesives, coatings, and materials for use in construction areas, and also in industrial, architectural, energy, electronics, 3D-printing, biomedical, and other related applications.

[0046] The dry mix mortar formulations according to the invention include dry cement, sand, and an innovative additive that includes clay, cellulose and starch (herein “Innovative Additive”).

[0047] The clay component includes synthetic clays, naturally derived clays, organic clays (e.g., modified clays) or combinations and blends thereof. In certain embodiments, the clay includes Smectite clay, Attapulgite clay or combinations and blends thereof. The Smectite clay is selected from the subclasses of bentonite, hectorite, Sepiolite, or combinations and blends thereof. The Attapulgite clay is selected from the Palygorskite mineral class. In certain embodiments, the Innovative Additive includes one of Smectite or Attapulgite clay. In other embodiments, the Innovative Additive includes a combination or blend of Smectite and Attapulgite clays. For example, the clay is selected from hectorite, bentonite, Sepiolite, Attapulgite, or a combination or blend thereof.

[0048] The clay is present in the Innovative Additive in an amount selected from a range that includes a lower endpoint and an upper endpoint. In certain embodiments, the lower endpoint is greater than 0 weight percent clay and the upper end point is less than 100 weight percent clay, based on the total weight of the Innovative Additive. In other embodiments, the lower endpoint is 5 weight percent or greater and the upper endpoint is 95 weight percent or less of clay, based on the total weight of the Innovative Additive. In still other embodiments, the lower endpoint is selected from 10, 15, 20, 25, 30, 35, 40, 45, or 50 weight percent or greater of clay and the corresponding upper endpoint is selected from 90, 85, 80, 75, 70, 65, 60, 55 or 50 weight percent or less of clay, based on the total weight of the Innovative Additive. In certain embodiments, the clay is present in a range having a lower endpoint of 5 weight percent and an upper endpoint of 90weight percent (from 5 to 90 wt.%) or a lower endpoint of 40 weight percent and an upper endpoint of 80 weight percent (from 40 to 80 wt.%), based on the total weight of the Innovative Additive.

[0049] Without intending to be bound by any particular theory, it is believed that presence of the Innovative Additive in a maximum amount (highest beneficial percentage), produces a dry (e.g., tile) mortar formulation having one or more of the aforementioned improved properties (e.g., ease of application, durability, sag control, water retention, viscosity buildup, tile slide resistance, and extended or prolonged open time).

[0050] The cellulose component includes, but is not limited to, methyl hydroxyethyl cellulose (MHEC), methyl hydroxypropyl cellulose (MHPC), hydroxypropyl cellulose (HPC), methyl cellulose (MC), ethyl hydroxyethyl cellulose (EHEC), methyl ethyl hydroxyethyl cellulose (MEHEC), hydroxyethyl cellulose (HEC), and combinations or blends thereof. The cellulose component according to the invention provides improved water retention properties to ensure that the mortar remains workable for an extended period of time, as well as contributing to viscosity buildup, providing a stable and consistent mixture.

[0051] The cellulose is present in the Innovative Additive in an amount selected from a range that includes a lower endpoint and an upper endpoint. In certain embodiments, the lower endpoint is greater than 0 weight percent and the upper end point is 90 weight percent or less of cellulose, based on the total weight of the Innovative Additive. In other embodiments, the lower endpoint is 1 weight percent or greater and the upper endpoint is 45 weight percent or less of cellulose, based on the total weight of the Innovative Additive. In still other embodiments, the lower endpoint is selected from 5, 10 or 15 weight percent or greater and the corresponding upper endpoint is selected from 20, 30 or 40 weight percent or less of cellulose, based on the total weight of the Innovative Additive. In certain embodiments, the cellulose is present in a range having a lower endpoint of 5 weight percent and an upper endpoint of 90 weight percent (from 5 to 90 wt.%) or a lower endpoint of 10 weight percent and an upper endpoint of 30 weight percent (from 10 to 30 wt.%), based on the total weight of the Innovative Additive.

[0052] The starch component includes but is not limited to starch ethers, such as, hydroxypropyl starches, hydroxypropyl carboxymethyl starches, partially crosslinked starches, carboxymethyl starches, and combinations or blends thereof. The starch component according to the invention delays the setting of cement, thereby providing an extended open time that results in more flexibility during application and adjustment of tiles.

[0053] The starch is present in the Innovative Additive in an amount selected from a range that includes a lower endpoint and an upper endpoint. In certain embodiments, the lower endpoint is greater than 0 weight percent and the upper end point is 50 weight percent or less of starch, based on the total weight of the Innovative Additive. In other embodiments, the lower endpoint is 1 weight percent or greater and the upper endpoint is 45 weight percent or less of starch, based on the total weight of the Innovative Additive. In still other embodiments, the lower endpoint is selected from 5, 10 or 15 weight percent or greater and the corresponding upper endpoint is selected from 20, 30 or 40 weight percent or less of starch, based on the total weight of the Innovative Additive. In certain embodiments, the starch is present in a range having a lower endpoint of 2 weight percent and an upper endpoint of 40 weight percent (from 2 to 40 wt.%) or a lower endpoint of 5 weight percent and an upper endpoint of 20 weight percent (from 5 to 20 wt.%), based on the total weight of the Innovative Additive.

[0054] In certain embodiments, the Innovative Additive is composed of 85 weight percent of clay, 10 weight percent of cellulose, and 5 weight percent of starch, based on the total weight of the Innovative Additive.

[0055] In addition to the Innovative Additive, the dry mix mortar formulations optionally include one or more other additives known in the art for use in traditional dry mix (e.g., tile) mortar formulations, such as but not limited to one or more of a polymer, cure accelerator, colored pigment, filler, and combinations or blends thereof.

[0056] Suitable polymer(s) include but are not limited to styrene-acrylics, vinyl acetate ethylene (VAE) copolymer, polyvinyl acetates (PVAc), acrylics, styrene butadiene rubber (SBR), and combinations or blends thereof.

[0057] In certain embodiments, the polymer(s) is / are present in the dry (e.g., tile) mortar formulation in an amount selected from a range that includes a lower endpoint and an upper endpoint. In certain embodiments, the lower endpoint is greater than 0 weight percent and the upper endpoint is 25 weight percent or less, based on the total weight of the dry mortar formulation. In other embodiments, the lower endpoint is 1 weight percent or greater and the upper endpoint is 20 weight percent or less, based on the total weight of the dry mortar formulation. In still other embodiments, the lower endpoint is selected from 1.5 or 10 weight percent or greater and the corresponding upper endpoint is selected from 20 or 15 weight percent or less (e.g., from 1.5 to 20 wt.% or from 10 to 15 wt.%), based on the total weight of the dry tile mortar formulation.

[0058] In certain embodiments, the Innovative Additive is present in dry mix (e.g., tile) mortar formulation in an amount selected from a range that includes a lower endpoint and an upper endpoint based on the total weight of the dry tile mortar formulation. In certain embodiments, the lower endpoint is greater than 0 weight percent and the upper end point is 25 weight percent or less of Innovative Additive, based on the total weight of the dry mix (e.g., tile) mortar formulation. In other embodiments, the lower endpoint is 0.5 weight percent or greater and the upper endpoint is 20 weight percent or less of the Innovative Additive, based on the total weight of the dry mix (e.g., tile) mortar formulation. In still other embodiments, the lower endpoint is selected from 1 or 5 or 10 weight percent or greater and the corresponding upper endpoint is selected from 5 or 10 or 15 weight percent or less of the Innovative Additive, based on the total weight of the dry mix (e.g., tile) mortar formulation. In certain embodiments, the Innovative Additive is present in a range having a lower endpoint of 0.1 weight percent and an upper endpoint of 7.0 weight percent (from 0.1 to 7.0 wt.%) or a lower endpoint of 0.5 weight percent and an upper endpoint of 4.0 weight percent (from 0.5 to 4.0 wt.%), based on the total weight of the dry mix mortar formulation.

[0059] In addition to the aforementioned additives, the dry mix (e.g., tile) mortar formulations include cement and sand, e.g., silica.

[0060] Suitable cements include, but are not limited to, Ordinary Portland Cement (OPC), Portland Pozzolana Cement (PPC), rapid hardening cement, slag cement, high alumina cement, quick setting cement, and combinations or mixtures thereof. The amount of cement can vary. In certain embodiments, the cement is present in an amount from 20 to 65 weight percent or from 30 to 60 weight percent of from 25 to 50 weight percent based on the total weight of the dry mix (e.g., tile) mortar formulation. In certain embodiments, the cement comprises from 20 to 50 weight percent or from 22 to 40 weight percent, based on the total weight of the dry mix mortar formulation.

[0061] In certain embodiments, the sand for use in the dry mix (e.g., tile) mortar formulation is silica. Silica sands are available in various U. S. mesh (sieve) sizes ranging from 4 to 200 corresponding to different millimeter sizes. A lower U. S. mesh size of silica sand corresponds to a coarser size distribution, and is commonly used for abrasive blasting, filtration systems, and concrete mixes; a higher U. S. mesh size silica sand refers to a finer size distribution, and is preferred for glass manufacturing, ceramics, and metal casting. The amount of sand can vary. In certain embodiments, the sand is present in an amount from 30 to 80 weight percent or from 40 to 70 weight percent of from 50 to 65 weight percent based on the total weight of the dry mix (e.g.,tile) mortar formulation. In certain embodiments, the sand comprises from 30 to 80 weight percent or from 50 to 70 weight percent, based on the total weight of the dry mix mortar formulation.

[0062] The dry mortar formulation is then combined with water to form a wet (e.g., paste) mortar formulation.

[0063] A tile mortar formulation according to certain embodiments of the invention is as follows.Raw Material Dosage (Cement 33Silica Sand 30 X 50 (0.6-0.3 mm) 30Silica Sand 140 (0.1 mm) 35Redispersible Polymer 1.5Innovative Additive 0.5Water 22.3

[0064] In certain embodiments, the “Redispersible Polymer” indicated above is water-redispersible vinyl acetate / ethylene copolymer powder.

[0065] The Innovative Additive in the above tile mortar formulation includes 85% clay, 10% cellulose and 5% starch, based on the total weight of the Innovative Additive.

[0066] According to the invention, the dry mix (e.g., tile) mortar formulation is prepared by selecting and mixing the additives in their respective amounts, then mixing the (mixed) additives with the other formulation raw materials, adding water and subsequently applying the wet mortar to a surface of a tile to be placed or a surface (e.g., concrete slab) on which the tile is to be placed.

[0067] In certain embodiments, the wet mortar mixing step is performed as follows. Prepare (e.g., at least 2 kg) dry powder adhesive. Based on the percent water value that is obtained by using flow table values (17.5 cm to 21.0 cm diameter), pour the determined amount of water in a mixer, e.g., Hobart paddle mixer. Add the dry powder over the liquid and mix (e.g., for 30 seconds). Scrape down the mixer paddle and sides of the mixer bowl (e.g., within 1 minute). Replace the paddle, and mix again (e.g., for another 1 minute). In certain embodiments, the total mixing time is 90 seconds. Let the mortar sit and mature for 5 minutes (“Slake time”) and then mix again (e.g., for another 15 seconds).

[0068] In certain embodiments, applying the wet mortar includes the following steps. Apply a thin layer of the mortar to a concrete slab, e.g., with a straight edge trowel, then apply a thick layer onto the surface of the thin layer, and comb with a notched trowel, e.g., having 6 mm x 6 mmnotches at 12 mm centers. The trowel is held at an angle of approximately 60° to the substrate, at a right angle to one edge of the slab and drawn across the slab parallel to that edge (in a straight line). After approximately 30 minutes (or 45 minutes), tiles (e.g., approximately ten or more) are incrementally spaced on the mortar. A 2-kg weight is placed on each tile and allowed to remain for approximately 30 seconds, prior to removing the weight. After 27-day storage under standard conditions, time mortar adhesion pull-off test square head plates are adhesively bonded to each of the tiles with a suitable high strength adhesive (e.g., epoxide adhesive). After a further 24-hour storage under standard conditions to permit the epoxide to cure, the tensile adhesion strength of the adhesive is determined by applying a force increasing at a constant rate of (250 ±50) N / s using a pull-off test instrument.

[0069] In certain embodiments, the concrete slabs are at least 35 mm thick and are stored for 24 hours under standard conditions. After the initial 24 hours, the slabs are then submerged in water for six days. This process, known as water curing, ensures that the concrete slabs remain hydrated and free of dust and other particles, and contributes to improved strength and durability. Thirty minutes prior to the mortar application, the concrete slabs are removed from the water, and the excess water is wiped off the surfaces.

[0070] In addition, in certain embodiments, the tiles used for this method are glazed porous body tile, group Bill, of water absorption (15 ± 3) % by mass, with a thickness in the range 7 mm to 10 mm and a profile back pattern less than 0,25 mm deep, cut to facial dimensions of (50 ± 1) mm x (50 + 1) mm.

[0071] In certain embodiments, the ceramic tiles used for the tile adhesion test are manufactured to 50 mm x 50 mm dimensions and supplied by Rocholl (Biscuit tiles, glazed, white; Rocholl GmbH, Eschelbronn, Germany) and are used as received (“manufactured tiles”). At other times, ceramic tiles with dimensions of 100 mm x 100 mm supplied by Daltile (Tile D31722MS1P; Daltile. Cranberry, NJ, US) are cut into four pieces with a tile saw. each measuring 50 mm x 50 mm and then washed with water to remove any dust particle (“cut tiles”).EXAMPLESExample 1

[0072] The preferred embodiment for the dry tile mortar formulation includes the Innovative Additive, which includes clay at a concentration of 85% by weight, cellulose at 10% by weight, and starch at 5% by weight, based on the total weight of the Innovative Additive. These concentrations were determined / determinable based on experimental data to achieve the desired properties of tile slide control, water retention, viscosity buildup, and extended open time.

[0073] The mortar formulations incorporating the Innovative Additive were prepared by blending the following components in the specified amounts: 33 wt. % of cement, 30 wt. % of silica sand 30 x 50 (0.6-0.3 mm), 35 wt. % of silica sand 140 (0.1 mm), 1.5 wt. % of redispersible polymer, 0.5 wt. % of Innovative Additive, and 22.3 g of water per 100 g of mortar.

[0074] A Control sample in this example was composed of only clay and cellulose.

[0075] The Innovative Additive and Control formulas in percentages based on weight, and the corresponding mortars made containing them, are shown Table 1. Also shown in Table 1 are the flow table result, water demand, and 30-minute and 45-minute open times, 28-day cured tile adhesion results. The raw material details and vendors are shown in Table 2.Table 1Control AdditiveHectorite Bentone CT 90.0%Cellulose Lotte ETC 5010 10.0%100.0%Control MortarCement Sakrete OPC Cement (Type I-II) 33.0%Sand 1 PFS Sand 30x50 (0.6-0.3 mm) 30.0%Sand 2 PFS Sand 140 (0.1 mm) 35.0%Polymer 1 Dairen DA 1105 1.5%C ontrol Additive 0.5%100.0%Flow Table Result 17.7 cmWater Demand 19.2 / 100 g30-min Tile Adhesion 80+ / - 8 PSI45 min Tile Adhesion 62 + / - 10 PSIPreferred Innovative AdditiveHectorite Bentone CT 85.0%Cellulose Lotte ETC5010 10.0%Starch ADM Calset PR 3010 5.0%100.0%Innovative MortarCement Sakrete OPC Cement (Type I-II) 33.0%Sand 1 PFS Sand 30x50 (0.6-0.3 mm) 30.0%Sand 2 PFS Sand 140 (0.1 mm) 35.0%Polymer 1 Dairen DA 1105 1.5%Preferred Innovative Additive 0.5%100.0%Flow Table Result 19.1 cmWater Demand 22.3 g / 100 g30-min Tile Adhesion 167+ / - 16 PSI45 min Tile Adhesion 113 + / - 5 PSITable 2Material Type: Supplier: Ingredient Trade Name: CharacteristicsClay: Elementis PLC: Bentone CT: natural, untreated Hectorite clayCellulose: Lotte Fine Chemicals: ETC 5010: modified cellulose, viscosity 43,000-57,000 mPa s Starch: ADM: Calset PR 3010: modified starchPolymer: Dairen Chemical Corp.: DA 1105: VAE redispersible polymer, glass transition temp, range 12 to 18 °CSand 1: PFS Aggregates: PFS Sand 30x50 (0.6-0.3 mm): silica sandSand 2: PFS Aggregates: PFS Sand 140 (0.1 mm): silica sandCement: Sakrete: Portland Cement Type I-II; powdered Ordinary Portland Cement (OPC)

[0076] For this Example, the water demand was determined by a flow table result between 17.5 cm and 19.5 cm. The concrete test slabs were obtained from TACM (16” x 16” x 1.5” Light Texture Test Blocks; Technical Concrete, El Cajon, CA, USA). The tiles used were “cut tiles” from Daltile. The water was added to the dry mortar compositions (including the Control Additive / Control Mortar and the Innovative Additive / Innovative Mortar) to form wet mortar compositions. The wet mortar was troweled onto a cement slab and, subsequently, after a 30-minute open time 10 tiles each were applied to the troweled wet mortar composition and after a 45-minute open time an additional 10 tiles each were applied to the troweled wet mortar compositions, as is shown in FIG. 1. The mortar bonded tiles were allowed to cure at standardconditions for 28 days. After day 27 of the 28 days had passed, square aluminum 50 mm x 50 mm pull-off dollies (Proceq #346105038 from Screening Eagle, Aliqippa, PA, US) were bonded to the top surfaces of each tile with epoxy adhesive from Loctite (#9340 Hysol - Green Epoxy High Temp). On the 28thday, a Proceq DY 216 Pull-off Tester (#34620000 from Screening Eagle) was used to pull the tiles off the mortar and to measure the resulting tensile adhesion. The tensile adhesion results of each 30-minute and 45 -minute open time series were tabulated from high to low. For all series of measurements of the 10 tiles, the two highest and the two lowest results were universally excluded in every case to reduce the noise from any outliers which commonly occur with type of tile adhesion testing. The middle 6 tile adhesion results were then averaged and reported along with the calculated standard of deviation for those 6 middle results.

[0077] In accordance with ISO 13007-1 standards, a tile mortar is classified as having an extended open time if it achieves a tensile adhesion strength of at least 72.5 psi (0.5 N / mm2) or greater after a 30-minute open time period. The Innovative Additive formulation shown in Table 1 demonstrated a significant improvement in performance, with an average tensile tile adhesion strength of 167 ± 16 psi at the 30-minute open time. Furthermore, the tensile adhesion strength at 45-minute open time was recorded at 113 ± 5 psi, surpassing the required threshold of 72.5 psi (0.5 N / mm2). These results were compared to the Control formulation which had tile adhesion strengths for 30-minute open time of 80 + / - 8 PSI, and for the 45-minute open time it produced only 62 + / - 10 PSI, i.e., below the required threshold of 72.5 psi (0.5 N / mm2), as shown in Table 1. The results are illustrated in a bar graph in FIG. 2.Conclusion

[0078] The experimental data illustrates that the tile mortar formulation containing the Innovative Additive not only meets, but significantly exceeds, the tensile adhesion strength requirement of 72.5 psi (0.5 N / mm2) for extended open times of 30 and 45 minutes. The formulation maintained robust adhesion properties even after 45 minutes, thereby confirming its suitability for applications requiring prolonged open times.Example 2

[0079] A number of Innovative Additive formulas within the ranges cited in the aforementioned description were prepared and tested in mortars as additional examples. The techniques andmethods used were the same as those described in Example 1 above. The ceramic tiles used for the open time tile bonding were the “manufactured” tiles that used the preparation method and testing protocols described in Example 1. Concrete test slabs which were used were obtained from Rocholl (40 cm x 40 cm x 4 cm type “Rocholl” concrete slabs; Rocholl GmbH, Eschelbronn, Germany). Water demand was determined by Flow Table using the limits of 19.0 cm to 21.0 cm. The slightly larger Flow Table range was needed to adjust for new Lots of sand and cement which were used in this example as compared to previous Example 1.

[0080] There are various ingredient level ranges described in the Innovative Additive formula and also in the mortar formulas in the previous descriptions. The samples prepared in this Example 2 are representative examples of formulas across those ranges.Experimental Data

[0081] The ingredients used to make the samples are shown in Table 3. The formulas for each Innovative Additive (IA) and mortar formula are shown in Table 4 and show the percentage of each ingredient based on weight. The flow table, water demand, 30-minute and 45-minute open time 28-day cured tile adhesion results are also shown in Table 4.Table 3Table 4Polymer 1 Polymer 1 VinnaPas 501 0 N 4 00% IA12 0 93%100 00%Table 4 ContinuedTable 4 ContinuedTable 4 ContinuedTable 4 Continued

[0082] FIG. 3 shows a graph of the water demand determined for each mortar in this example.

[0083] FIG. 4 shows a graph of the 30-minute and 45-minute open time tile adhesion results for each mortar. For the open times which are shown as 16 PSI, however, the actual open times were below the lower threshold of the pull-off tensile tester, as the tester has a lower limit of 16 PSI and will only return a 16 PSI result for all cases where the tensile adhesion force is below that threshold.The results show that the Innovative Additive made with various combinations of clays, celluloses, and starches when incorporated into several different mortar formulas provide bonded ceramic tile tensile adhesion results for 30 min open times that exceed the 72.5 PSI requirement in the test standard. Passing results are also obtained at 45 min open time for many of the mortar formulas containing the Innovative Additive. Several “Control” samples are included in the list of Innovative Additive formulas which were evaluated (mortars 11, and 28-33). The results of the Control mortars are comparable against the Innovative Additive invention.Conclusion

[0084] The results demonstrate that the Innovative Additive provides ceramic tile adhesion performance exceeding the requirement for 30-min open times and even 45-min open times.Example 3

[0085] For a selected subset of the Innovative Additive samples and their corresponding mortars presented in Example 2, tile slip (“Slip Resistance”) was evaluated. ISO- 13007-2 sub 4.2 describes the standard test method. In this Example 3, for brevity, the procedure used was adapted from the standard test method, which is commonly used by mortar manufacturers in their lab testing facilities. ISO 13007-2 sub 5.2 specifies a <0.5 mm tile slip as a mortar performance requirement (“Slip Resistance” in Table 3 of the test method). In practice, mortar manufacturers can allow up to 1.0 mm tile slip as the maximum allowable tile slip which is accepted by them as passing.Procedure

[0086] The dry mortar was mixed with water in the same manner as was used in the previous examples herein. The amount of water for each mortar used in this example was the same amount that was determined for each individual mortar from water demand flow table evaluations performed in Example 2. A concrete test slab (as described above) was laid flat or horizontal on a bench surface. An initial thicker layer of wet mortar was then applied to the surface of the concrete substrate using a trowel and spread evenly. The wet mortar was combed at right angles to the concrete slab edge using a notched trowel having 6 mm x 6 mm notches at 12 mm centers. The trowel was held at an angle of 60° to the substrate and parallel to the concrete slab edge when making the grooves. The spread and grooved mortar was allowed to set undisturbed on the concrete slab for 2 minutes. After the 2 minutes had expired, a type Bia ceramic tile (as described in sub 4.2.2.1 of ISO-13007-2 ) was laid flat on the grooved wet mortar. Then a 50 N weight was placed on the tile for 30 seconds. During this 30-second time waiting period, a trowel edge was used to make a straight reference line notched groove immediately along what would be the bottom edge of the tile when the concrete slab was repositioned as vertically orientated. This notched groove was the reference line for measuring how far the tile slid beyond it (i.e., tile slip). At the end of the 30 seconds, the weight was removed from the tile, and the concrete slab was tilted from its current horizontal position to vertical, and this orientation was maintained for the remainder ofthe test. FIG. 5 shows an example of the tile slip testing of Mortar 21 when the concrete slab had been raised to a vertical position. After 20 min of vertical orientation of the concrete slab, a caliper was used to measure the distance that the tile had slid past the notched groove reference line, and the result was reported.

[0087] The results of the tile slip evaluations are shown in Table 5 below.Table 5: Results of Tile Slip Evaluations of some of the mortars from Example 2

[0088] Several of the mortars derived from the various Innovative Additives meet this requirement of additionally providing a passing Slip Resistance result. For those that failed, it is likely that the water demand was not correctly adjusted. In Example 2, water demand was specified as the amount of water that would allow the mortar formulation to produce a Flow Table evaluation result of 19.0 cm - 21.0 cm. In (commercial) practice, the water demand of each individual mortar can vary depending on the mortar formula composition, and the water demand amount could be uniquely optimized for each to simultaneously produce the optimized mix of performance properties like tile adhesion strength, Slip Resistance, Transverse Deformation, workability, and other mortar properties considered for mortar application (e.g., as specified in ISO 13007-2 sub5.2). Each individual mortar could undergo an optimization process to determine the water demand amount to produce the desired overall mortar performance.Conclusion

[0089] The results demonstrate that the Innovative Additives that provide tile tensile adhesion strength which meet industry requirements of >72.5 PSI (0.5 N / mm2) for extended open time are also able to provide acceptable tile slip resistance for certain mortar examples.

Claims

We claim:

1. A dry mix mortar formulation, comprising:sand;cement; andInnovative Additive comprising:a clay comprising one or more of bentonite, hectorite, Sepiolite, and Attapulgite;a cellulose; anda starch,wherein, the dry mix mortar formulation when combined with water to form a wet mortar demonstrates an extended open time.

2. The dry mix mortar formulation of claim 1, wherein the clay comprises a range having a lower endpoint of 5 weight percent and a corresponding upper endpoint of 90 weight percent or a lower endpoint of 40 weight percent and a corresponding upper endpoint of 80 weight percent, based on the total weight of the Innovative Additive.

3. The dry mix mortar formulation of claim 1, wherein the cellulose comprises a range having a lower endpoint of 5 weight percent and a corresponding upper endpoint of 90 weight percent or a lower endpoint of 10 weight percent and a corresponding upper endpoint of 30 weight percent, based on the total weight of the Innovative Additive.

4. The dry mix mortar formulation of claim 1, wherein the starch comprises a range having a lower endpoint of 2 weight percent and a corresponding upper endpoint of 40 weight percent or a lower endpoint of 5 weight percent and a corresponding upper endpoint of 20 weight percent, based on the total weight of the Innovative Additive.

5. The dry mix mortar formulation of claim 1, wherein the cellulose is selected from methyl hydroxyethyl cellulose, methyl hydroxypropyl cellulose, hydroxyethyl cellulose, and combinations and mixtures thereof.

6. The dry mix mortar formulation of claim 1, wherein the starch is selected from hydroxypropyl starch, hydroxypropyl carboxymethyl starch, carboxymethyl starch, and combinations and mixtures thereof.

7. The dry mix mortar formulation of claim 1, wherein the Innovative Additive comprises a range having a lower endpoint of 0.1 weight percent and an upper endpoint of 7 weight percent or a lower endpoint of 0.5 weight percent and an upper endpoint of 4 weight percent, based on the total weight of the dry mix mortar formulation.

8. The dry mix mortar formulation of claim 1, wherein the Innovative Additive comprises:85% by weight of the clay;10% by weight of the cellulose; and5% by weight of the starch,based on the total weight of the Innovative Additive.

9. The dry mix mortar formulation of claim 1, wherein the starch is a starch ether.

10. The dry mix mortar formulation of claim 1, wherein the sand comprises silica.

11. The dry mix mortar formulation of claim 10, wherein silica has a mesh (sieve) size from 4 to 200.

12. The dry mix mortar formulation of claim 1, wherein the sand comprises from 30 to 80 weight percent or from 50 to 70 weight percent based on the total weight of the dry mix mortar formulation.

13. The dry mix mortar formulation of claim 1, wherein the cement comprises from 20 to 50 weight percent or from 22 to 40 weight percent based on the total weight of the dry mix mortar formulation.

14. The dry mix mortar formulation of claim 1, further comprising one or more of a polymer, cure accelerator, colored pigment, filler, and combinations or blends thereof.

15. The dry mix mortar formulation of claim 14, wherein the polymer is selected from the group consisting of styrene-acrylic, vinyl acetate ethylene copolymer, polyvinyl acetate, acrylic, styrene butadiene rubber, and combinations or blends thereof.

16. The dry mix mortar formulation of claim 14, wherein the polymer comprises a range having a lower endpoint of 1, 1.5 or 10 weight percent and the upper end point is 20, 15, or 10, based on the total weight of the dry mix mortar formulation17. The dry mix mortar formulation of claim 1, comprising:0.5 weight percent of the Innovative Additive;33 weight percent of the cement;65 weight percent of the silica; and1.5 weight percent of the polymer,based on the total weight of the dry mix mortar formulation.

18. A wet tile mortar formulation, comprising:the dry tile mortar formulation of claim 1; andwater.

19. The wet tile mortar formulation of claim 18. wherein based on a percentage of water the water demand is 22.3%.

20. The wet tile mortar formulation of claim 18. wherein the tensile adhesion strength meets or exceeds 72.5 psi (0.5 N / mm2) after a 30-minute open time period.

21. The wet tile mortar formulation of claim 18, wherein the tensile adhesion strength meets or exceeds 72.5 psi (0.5 N / mm2) after a 45-minute open time period.

22. A method for preparing a dry mix mortar formulation, comprising:preparing an Innovative Additive, comprising:combining:a clay comprising one or more of bentonite, hectorite, Sepiolite, and Attapulgite;a cellulose; anda starch; andmixing the Innovative Additive with cement and sand.

23. The method of claim 22, further comprising combining the dry mix mortar formulation with water forming a wet mortar that demonstrates an extended open time.

24. The method of claim 22, wherein the cellulose is selected from methyl hydroxyethyl cellulose, methyl hydroxypropyl cellulose, hydroxypropyl cellulose, methyl cellulose, ethyl hydroxyethyl cellulose, methyl ethyl hydroxyethyl cellulose, and hydroxyethyl cellulose, and combinations and mixtures thereof.

25. The method of claim 22, wherein the starch is selected from hydroxypropyl starch, hydroxypropyl carboxymethyl starch, carboxymethyl starch, and combinations and mixtures thereof.

26. A method for preparing a wet tile mortar formulation, comprising:preparing the dry mix mortar formulation according to claim 21; and adding water to the dry mix mortar formulation.

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